Hypereosinophilic conditions have been studied extensively, and we have identified new markers that distinguish between several important variants of this syndrome. We have instituted new therapies (imatinib, anti-IL5) for the treatment of each of these variants. [unreadable] [unreadable] The interaction between helminth infeciton and allergic disease has been studied using epidemiological tools coupled with physiological measurements of allergic disease and immunological assessments. We have demonstrated that chronic helminth infection protects against allergic diseases. Studies done to date have demonstrated the CD4+ cells (and neither the monocytes nor the basophils) are the overwhelmingly major source of IL-10 in chronic filarial infection. We have also demonstrated that IgE mediated responses persist for decades even in the absence of antigen stimulation.